The need to improve the quality and safety of hospital care in the United States is well-recognized. Quality improvement collaboratives, in which multi-disciplinary teams from different hospitals unite around a common improvement goal, are a popular method for accelerating improvement efforts, both in the United States and abroad. Working collaboratively, hospitals share knowledge about methods to translate clinical innovations into routine practice. Although collaboratives make intuitive sense, they are costly to carry out, and evidence of their benefit is limited. Most significantly, little is known about the sources of performance variation among hospitals participating in the same collaborative, or about the strategies that participants can engage in to increase the likelihood that they will be successful. The Premier healthcare alliance recently launched QUEST, a 3 year collaborative that has enrolled more than 160 hospitals from a network of more than 550 hospitals nationwide. QUEST aims to improve hospital performance across multiple domains of quality, including increasing adherence to evidence based care, reducing costs, improving patient satisfaction, and decreasing rates of complications. One of the most ambitious goals of the QUEST collaborative is to reduce risk-adjusted hospital mortality rates. To accomplish this, collaborative participants are attempting to implement more than a dozen clinical practices, ranging from sepsis bundles to rapid response teams, intended to improve survival for patients with high-risk clinical conditions like sepsis and respiratory failure. The primary aim of this study is to investigate the sources of variation in the implementation of recommended clinical practices by collaborative participants by applying a theoretical framework for analyzing implementation effectiveness that is well known in business but relatively new to healthcare. To accomplish this we will survey clinical and administrative leaders at QUEST hospitals in order to assess how perceptions of collaborative-recommended clinical practices, together with the hospital implementation climate and strategies, influence the chances of successful implementation of collaborative recommended practices (Aim 1). We will then examine the association between the implementation of recommended clinical practices and change in complication and mortality rates at participating hospitals (Aim 2). Finally, we will conduct a rigorous evaluation of the overall impact of the collaborative by examining changes in complication and risk-adjusted mortality rates over time at participating and non-participating hospitals (Aim 3). Developing a greater understanding of the benefits of the collaborative approach, and of the contextual factors and strategies that enable some hospitals to excel, will provide actionable information to current and future collaborative participants and organizers, and will increase the effectiveness of quality improvement efforts. PUBLIC HEALTH RELEVANCE: A common approach for improving the quality and safety of hospital care in the United States involves bringing teams of doctors and nurses together from different hospitals to work collaboratively towards a common improvement goal. While the concept makes sense, quality improvement collaboratives are costly to run, and evidence of their benefit is limited. More importantly, little is known about why, within the same collaborative, some hospitals are more successful than others. Through surveys of senior hospital leaders and quality improvement staff, this study will examine how perceptions of new clinical practices, together with other hospital factors, contribute to successful implementation efforts. Additionally, this study will evaluate the effects of a large quality improvement collaborative focused on reducing hospital complication and death rates.